Apparatus relating to evacuating and filling gas discharge lamps and the like



REYNDERS APPARATUS RELATING TO EVACUATING AND FILLING GAS March 28, 1967 DISCHARGE LAMPS AND THE LIKE 2 Sheets-Sheet 1 Filed July 6, l964 FiGi INVENTOR.

REYNDERS ANTON A. R NDERS 3,311,440 NG TO ACUATING AND FILLING GAS 2 Sheets-Sheet 2 IN VEN TOR. ANTON REYNDERS AGENT APPARATUS RELATI DISCHARGE LAMPS AND THE LIKE arch 28, 1967 Filed July 6, 1954 United States Patent 3 311 440 APPARATUS RELATING ro EVACUATING AND FILLING GAS DISCHARGE LAMPS AND THE LIKE Anton Reyuders, Emmasingel, Eindhoven, Netherlands, assignor to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware Filed July 6, 1964, Ser. No. 380,324 Claims priority, application Netherlands, July 11, 1963, 295 212 5 Claims. (Cl. 316-30) The invention relates to an apparatus for evacuating gas discharge tubes or the like and introducing an accurately controlled quantity of mercury into each of them. Such apparatus comprises holders by which a plurality of tubes may be conveyed in a horizontal position in a direction at right angles to their longitudinal axes, pairs of heads arranged to follow the movement of the said holders and to be connected to an evacuating system, the exhaust tubes projecting from both ends of a discharge tube: being inserted one into each of a pair of heads, and means for introducing a cont-rolled quantity of mercury into the evacuated tube through one of the exhaust tubes at a desired instant. Such an apparatus is known.

In a known apparatus there is provided for each tube, a moving container filled with mercury and during each revolution of the apparatus a controlled quantity of mercury is separated from the container and supplied to the tube concerned. Separating a controlled quantity of mercury and supplying it to a lamp or tube at a desired instant are operations which take place in the same head during the transport of the lamps. Consequently the construction of such a head is complicated.

It is desirable that exactly the same quantity of mercury should be introduced into each tube. However, to do so involves difficulties when multiple containers of mercury are used serving individual tube positions.

It is an object of the present invention to provide an apparatus which is not subject to difliculties, is of simpler construction, and which is particularly suitable for use with the machine described in co-pending application Ser. No. 380,238 in which I am a co-inventor.

The apparatus in accordance with the invention is characterized in that one head of each pair is provided with a supplying chamber situated adjacent the evacuation path of the tube. The chamber is provided with an inlet and an outlet adapted to be closed in a vacuum-tight manner, and when the said head moves past a stationary mercury dosing device a predetermined controlled amount of mercury for a single tube is supplied to the chamber. Thereafter the inlet is closed and the tube is evacuated. Means are provided by which at a desired instant after the evacuation of the tube the outlet of the supply chamber filled with a controlled amount of mercury for a tube may be opened while blowing means are arranged by which the controlled quantity of mercury, which after opening of the outlet of the supply chamber falls into a prepared position in the evacuation path, may be blown into the tube through the exhaust tube at another desired instant. Thus for each tube there is a supply chamber containing only one quantity of mercury for the said tube. Hence the said apparatus includes only a single mercury dosing device which always delivers an equal quantity of mercury to each of a plurality of sequentially passing heads of the apparatus. Thus the accuracy required for dosage needs only to be set once and can be checked more readily than is the case in the known prior apparatus. By using for each tube a supply chamber containing a controlled quantity of mercury for only a single tube or "ice lamp, the additional advantage is obtained that the correct mercury dose is prepared outside the evacuation path irrespective of the vacuum conditions. Furthermore, the mercury dose is brought into the evacuation path only at the last moment, that is when the tube has been sufiiciently evacuated.

Since the supply chamber contains a ,dose for a single tube only, a comparatively limited amount of mercury takes part in the operation of the entire apparatus so that the likelihood of oxidation and contamination of the mercury is very small in contradistinction to a construction in which a comparatively large supply of mercury is being conveyed for each tube. A further advantage consists in that the apparatus need not be stopped to replenish the supply of mercury as is the case in the known apparatus. The means for blowing the mercury into the tube preferably consist in momentarily supplying a rare gas, for example, argon.

The supply chamber for each tube may take the form of a space between an annular groove in a piston and in a cylinder enclosing the piston. This space communicates in one. of the positions of the piston with the inlet for a controlled quantity of mercury for a tube and in another position with the outlet to a prepared position in the evacuation path of the tube. The piston is preferably cont-rolled electroma'gnetically. To prevent reciprocating movements of the piston including the groove, in a preferred embodiment the holders and the heads for the tubes are arranged to move with a circular movement in a vertical plane and the supply chambers have a substantially cylindrical shape. The supply to each chamber is effected approximately tangentially through an aperture in the cylindrical wall in a position of the chamber in which its axis extends substantially horizontally while the chamber may be discharged, While being in a rotated position into which it is brought by a movement of the tubes, through an aperture in the base of the chamber which may be closed by a preferably apertured valve. The controlled amount of mercury is conveyed to its prepared position in the evacuation path by the rotary movement of the apparatus.

In order that the invention may readily be carried out, two embodiments thereof will now be described, by way of example, with reference to theiaccompanying diagrammatic drawings, in which:

FIG. 1 is a diagrammatic front elevation of an apparatus for evacuating gas discharge tubes or the like and introducing an accurately controlled quantity of mercury into each of them;

FIGS. 2 and 3 relate to a first embodiment of a head following the movement of each tube: FIG. 2 is a sectional view taken on the line II-II of FIG. 3 and FIG. 3 is an elevation taken in the direction indicated by the arrow III of FIG. 2;

FIGS. 4 and 5 relate to a second embodiment of the head. FIG. 4 is a sectional view analogous to FIG. 2 and FIG. 5 is a sectional view taken on the line V-V of FIG. 4.

FIG. 1 shows schematically an apparatus for evacuating gas discharge tubes and introducing a controlled quantity of mercury into each of them. In the apparatus the tubes (for example 1, 2, 3) are arranged to move along a circular path at a contact speed and in a horizontal position. The direction of movement is indicated in FIG. 1 by the arrow 5.

The tubes are held in horizontal position and are provided at their ends with open exhaust tubes which are inserted into heads arranged to be also moved in the direction indicated by the arrow 5. The arrangement is such that the tubes when inserted into the heads are connected to an evacuating system. This is, shown in more detail in FIG. 2 for a lamp tube 4, the exhaust tube or lamp stem 11 of which is disposed in a lamp closing member. The said closing member or head comprises a housing 15 and a resilient hollow plug 19 enclosed by a nut 17. By turning the nut 17 the plug may be compressed so as to surround the exhaust tube 11 in a vacuum-tight manner. The housing 15 has a bore 21 connected to an evacuation pipe 23. At the other end of the lamp tube 4 a similar head is provided which also includes a closure member for the stem in the form of a rubber plug and a bore connected to an evacuating system; this second head is not shown for the sake of simplicity.

One of the heads associated with each tube, for example, the head shown in FIG. 2, is so constructed as to include a supply chamber to which a controlled amount of mercury for only one lamp or tube may be supplied in a manner to be described hereinafter and held until the mercury is to be introduced into the lamp.

The apparatus of FIG. 1 is provided with only a single stationary mercury dosing device 9 so constructed that each time the head of FIG. 2 holding the tube passes under the said device a controlled amount of mercury is delivered. The construction of the dosing device 9 is not described in more detail because it may be of a known type.

The head of FIG. 2 further includes a sleeve 25 secured to the housing 15 by means of a nut 27. The sleeve forms a guide for a piston 29 containing an annular groove 31. The piston is connected by a connecting rod 33 to a block 35 acting as a magnet core. The piston is arranged to reciprocate under the influence of a coil 37 shown diagrammatically; the piston is compelled to move to the right in FIG. 2 against spring action. A block 39 as shown by broken lines in FIG. 2 and enclosing a ball stopcock 41 is secured to the housing 15. The block 39 which encloses the stop-cock 41 and includes a funnel-shaped part 43, in actual fact extends at right angles to the drawing (see FIG. 3). The ambient atmosphere may be excluded from bores 49 and 51 provided in the housing 15 and the sleeve 25 respectively by means of the stop-cock 41 which contains a duct 45. The funnel-shaped part 43 opens into the stop-cock 41. In the position shown there is no communication between the space Within the funnelshaped part 43 and the bores 49 and 51; in the position shown of the duct 45 in the stop-cock 41 no such communication is possible. The stop-cock may be turned 90, however, so that the funnel-shaped part 43 is in direct communication with the bores 49 and 51. The evacuation pipe 23 secured to the housing 15 opens into a space 53. When the piston 29 is moved to the right in FIG. 2 it may enter the space 53. The space 53 is in communica tion with the bore 21 through a duct 55. Through the evacuating path constituted by the pipe 23, the space 53, the duct 55, the bore 21 and the exhaust tube or lamp stem 11, the tube 4 communicates with an evacuating system.

The apparatus operates as follows:

We start from a location in which a head 15 et seq. passes under the dosing device 9. In this location the funnel-shaped part 43 extends upwards (position A of FIG. 1). The arrangement is such that the duct 45 in the stop-cock 41 (FIG. 2) is turned 90". Consequently the stop-cock is opened. The piston 29 has been brought into its left-hand position; in this position the groove 31 is exactly below the bores 49 and 51. At this location an accurately controlled quantity of mercury is introduced by the dosing device 9 into the funnel-shaped part 43 through free fall and under the normal atmospheric conditions. The accurately regulated amount of mercury, for example, one drop of mercury, will descend to the lowest part of the groove 31. When the piston 29 is moved to the right the groove 31 assumes the position shown in FIG. 2. The drop then is efiectively enclosed in a supply chamber consisting of groove 31 and the imperforate wall portion of cylinder 25. At the position B (FIG. 1) the stop-cock 41 is closed again. Beyond the location C the tube 4 is subsequently evacuated through the pipe 23. Hence a partial vacuum will also be created in the annular groove 31. While the tube 4 is being evacuated it moves in the direction indicated by the arrow 5. At the location D the desired partial vacuum in the tube 4 is achieved. The piston 29 is moved further to the right by suitable energisation of the coil 37. The funnelshaped part 43 now points downwards. By the movements of the piston 29 to the right in FIG. 2 the groove 31 enters the space 53, permitting the enclosed drop of mercury to fall through the duct 55 (in the direction of the arrow 57 in the position E.) The drop then lies before the orifice of the duct 21 which may be considered as a capillary; at this location the drop is designated by 59. At a subsequent instant, for example at the location F, the drop of mercury 59 is forced into the interior of the tube 4 through the duct 21 with the aid of a momentary supply of a rare gas, for example, argon from a pipe 61 (FIG. 2). For this purpose a valve 63 is momentarily opened. Along the portion F-G of the path of the tube its exhaust tubes or lamp stems 11 are sealed.

At the location G the evacuated tube containing the appropriate amount of mercury is taken from the machine. Hence the evacuating circuit is broken. At a location H between the locations G and A a new tube to be evacuated and provided with a controlled amount of mercury is placed in the machine and the cycle repeated. For the sake of clarity the path taken by the drop of mercury in the head is indicated by a curved arrow 65 in FIG. 3. This path includes a sharp bend; it is also indicated in FIGURE 1, for example, by an arrow 67 near the position C.

FIGS. 4 and 5 show another embodiment. The tube and the lamp stem are again designated by 4 and 11, respectively. The head of FIG. 4 comprises a housing 101 and a nut 103 by turning which a resilient plug 105' may be compressed so as to surround the exhaust tube 11 in a vacuum-tight manner. A part 111 provided with an insertion piece 113 adapted to be connected to a supply of argon is secured to the housing 101 by studs 109. The part 111 comprises a bore 115, a recess 117, bores 119, 121, 123, and 127 and a recess 129. The evacuating path of the tube 4 is constituted by a pipe 107 connected to an evacuation pipe, the recess 129, duct 127, the bore 125, the lamp stem 11 and the tube 4. The housing 101 further contains a cylindrical chamber 131 in which a valve provided with a bore 133 is arranged to reciprocate. The valve 135 has an enlarged part 137 which closes the chamber 131 in a substantially gastight manner.

Through the bore 133 in the valve 135 the chamber 131 is in open communication with the aforementioned evacuation path. As FIG. 5 shows, the housing 101 further includes a part 143 having a funnel-shaped collecting chamber 151. In this part 143 a stop-cock 147 provided with a duct is rotatable about an axis 149. The communication between the funnel-shaped collecting space 151 for a controlled quantity of mercury and the substantially cylindrical chamber 131 into which the duct 153 opens may be interrupted by the said stop-cock. When closed the chamber 131 constitutes a supply chamber for the amount of mercury to be blown into the tube 4.

The operation of the said head (FIGS. 4 and 5) is substantially the same as that of the head described with reference to FIGS. 2 and 3. At the location A a controlled quantity of mercury is supplied to the funnelshaped collecting chamber 151; the said quantity is supplied through ducts 145 and 153 substantially tangentially to the chamber 131, performs a rolling movement as indicated by the double arrow 155 and finally lies in the position indicated by 161. The stop-cock 145 is then rotated, the inlet is closed and the tube is evacuated.

When the head is moved in the direction indicated by the arrow 5 of FIG. 1 to the location D the position of the principal axis of the cylindrical chamber 131 is changed. In the location A this axis extends substantially horizontally but in the location D it points obliquely downwards, the valve portion 135 with smaller diameter being at the top and the portion 137 having the larger diameter being at the bottom. The drop of mercury 161 will roll along a generatrix of the cylindrical chamber 131 and reach a position designated by 163 in FIG. 4. At the location B the valve 135 is lifted from its conical seating 167 and similarly to what is the case in PEG. 2 the drop of mercury reaches a position designated 171 just in front of the narrow bore 123 in the evacuation path. Similarly to what has been described with reference to the first embodiment the drop 1'21 is then forced by means of increased pressure into the exhaust tube ill and the tube 4 through the pipe 113 by a momentary supply of argon.

What is claimed is:

1. Apparatus for manufacturing fluorescent lamps in which lamp-tubes having a lamp-stem at each end are conveyed in a closed path while in a horizontal position, the combination comprising, a wheel defining said closed path, a plurality of head members spaced about said wheel, said head member having means for receiving a lamp-stem in sealed relation, a head body portion having a channel communicating With said lamp-stem at one end, a supply chamber within said head means connected with said head for connecting said channel with an evacuation source, means connected with said head for connecting said channel with a source of discharge gas, and means for supplying a measured quantity of mercury to said channel; said last-named means comprising a supply means communicating with the exterior ambient atmosphere surrounding said head and the interior of said head, said supply means including means defining a supply chamber and a valve for closing said supply chamber from said ambient atmosphere and closure means for communicating said channel and said supply chamber for delivering a quantity of mercury from said supply chamber into said channel.

2. Apparatus for manufacturing fluorescent lamps aciii cording to claim 1 wherein said closure means comprises a piston, a cylinder surrounding the said piston; said means defining said supply chamber comprising an annular groove in said piston, means for slidably moving said piston between a first position wherein said annular groove communicates with said supply means, a second position wherein said groove is out of register with said supply means, and a third position in Which said groove is in communication with said channel.

3. Apparatus for manufacturing fluorescent lamps according to claim 1, wherein said supply means comprises a body member having duct therethrough, a rotatable stop cock in said body intersecting said duct, said stop cock having an aperture therethrough for registry with said duct in one position thereof and closing said duct upon rotation from said one position.

4. Apparatus for manufacturing fluorescent lamps according to claim 3 wherein said closure means oomprises a housing member having a funnel-shaped opening, a valve member axially movable in said opening for blocking and unblocking the exit from said opening, a tangential entrance to said opening, said exit from said opening communicating with said channel, said opening being positioned and arranged in said housing member for gravity discharge of a quantity of mercury in said opening at a determined attitude of said Wheel.

5. Apparatus for manufacturing fluorescent lamps according to claim 1 wherein said channel includes a capillary portion, said supply chamber communicating with said channel at the entrance of said capillary portion and said means connecting said channel with a source of discharge gas being connected with said channel remote from the entrance of said capillary portion.

References ited by the Examiner UNITED STATES PATENTS 2,494,923 1/1950 Yoder et al. 3l6-2() RICHARD H. EANES, 1a., Primary Examiner. 

1. APPARATUS FOR MANUFACTURING FLUORESCENT LAMPS IN WHICH LAMP-TUBES HAVING A LAMP-STEM AT EACH END ARE CONVEYED IN A CLOSED PATH WHILE IN A HORIZONTAL POSITION, THE COMBINATION COMPRISING, A WHEEL DEFINING SAID CLOSED PATH, A PLURALITY OF HEAD MEMBERS SPACED ABOUT SAID WHEEL, SAID HEAD MEMBER HAVING MEANS FOR RECEIVING A LAMP-STEM IN SEALED RELATION, A HEAD BODY PORTION HAVING A CHANNEL COMMUNICATING WITH SAID LAMP-STEM AT ONE END, A SUPPLY CHAMBER WITHIN SAID HEAD MEANS CONNECTED WITH SAID HEAD FOR CONNECTING SAID CHANNEL WITH AN EVACUATION SOURCE, MEANS CONNECTED WITH SAID HEAD FOR CONNECTING SAID CHANNEL WITH A SOURCE OF DISCHARGE GAS, AND MEANS FOR SUPPLYING A MEASURED QUANTITY OF MERCURY TO SAID CHANNEL; SAID LAST-NAMED MEANS COMPRISING A SUPPLY MEANS COMMUNICATING WITH THE EXTERIOR AMBIENT ATMOSPHERE SURROUNDING SAID HEAD AND THE INTERIOR OF SAID HEAD, SAID SUPPLY MEANS INCLUDING MEANS DEFINING A SUPPLY CHAMBER AND A VALVE FOR CLOSING SAID SUPPLY CHAMBER FROM SAID AMBIENT ATMOSPHERE AND CLOSURE MEANS FOR COMMUNICATING SAID CHANNEL AND SAID SUPPLY CHAMBER FOR DELIVERING A QUANTITY OF MERCURY FROM SAID SUPPLY CHAMBER INTO SAID CHANNEL. 